Conventional close-up photographing lenses are used principally in 35 mm film-based (i.e., silver chloride film) photography. Examples of such lenses are disclosed in Japanese Patent Application Kokai No. Hei 7-1330 and Japanese Patent Application Kokai No. Hei 7-294853.
Nevertheless, conventional close-up photographing lenses, such as those cited above, do not have a sufficiently long back focus for the image height required in high-performance electronic equipment, such as optoelectronic apparatus employing charge-coupled devices (CCDs) and the like as image detectors situated in the image plane. Consequently, the space between the most imagewise lens element and the image plane ends up being too small, making it difficult to accommodate filters, prisms and the like adjacent the image plane. In addition, conventional close-up photographing lenses do not have adequate imagewise telecentricity, resulting in unwanted "shading," making them unsuitable for use with optoelectronic equipment employing CCDs and the like.